Shallow Seas
The ninth episode of Mesozoic Earth, focusing on the shallow parts of the oceans. Animals featured *''Platecarpus'' *Hesperornis *''Tanystropheus'' *''Atopodentatus'' *''Mesolimulus'' *Rhamphorhynchus *Sea Pen *''Ophthalmosaurus'' *Belemnite *''Geosaurus'' *''Carinodens'' *Mussel *Squalicorax *Mosasaurus *''Liopleurodon'' *''Niobradine'' *Hesperornis *Tusoteuthis *Cimolichthys *Platecarpus *Belemnite *Tylosaurus *Squid *Ichthyornis *''Brodavis'' *Mosasaurus *Velociraptor Plot Sequence 1 A shoal of squid jet up from the deep in the middle of the Pacific Ocean. They gather near the surface to mate, but suddenly a small mosasaur swims through the shoal. This is a Platecarpus, one of the most specialized mosasaurs of its time. Another swims by the squid. They are doing this to distract their prey, Platecarpus have among the most complex hunting strategies of all animals in this time. Some open their nostrils to release air bubbles. This creates a “net” to trap the squid. More Platecarpus do the same and others quickly swim through the shoal to frighten their prey. This may have started out as a hunt but now it is becoming something of a game. The Platecarpus enjoy frightening the squid and trapping them with their bubble nets, but they are still hungry. One of the Platecarpus swims into the shoal and captures a few squid. The rest do the same and soon swim away. The water is empty apart from a few tentacles, slowly sinking, into the deep. Sequence 2 Sequence 3 The shallows are right above the continental shelves. However, in order to see the continental shelves, we must leave behind the shallows, and head, into the deep. A world where light is replaced by constant darkness. Some animals will never see light. Anchored to the ground are sea pens, the most primitive of animals. The earliest animals on Earth were similar to these invertebrates. They are pale white, and feed on the nutrients, that sink down from the warm bright shallows above. But the sea pens aren't alone. Countless red sand dollars lie here too. Sand dollars are sea urchins, who lack spines. They look like statues, but they aren't. A time-lapse reveals that they are in fact very active. They move very quickly and leave trails behind as they try and find food. They thrive down here too, and are also some of the most primitive animals on Earth. However, amongst all the animals here, one actually does go into the shallows. Moving around is a Mesolimulus horseshoe crab. These are not crabs, but more closely related to spiders and other arachnids. They have been around since long before the dinosaurs, a true living fossil. They have eyes, and can move faster than the sand dollars, in fact, they can be seen moving, but are still slow. He is on the hunt. The sand dollars are too hard and not the type of food for them, so he moves on. His eyes are primitive, only telling the difference between light and dark. He continues to move, now searching for works buried in the sand. Mesolimulus go onto beaches to lay their eggs, and this male is gearing up for that. Then, he finds a worm and sand clouds form and blur him as he excavates and captures his food. He continues to move around. Now he begins his epic journey from the deep, and towards the beach. As he moves, he joins others, all on the same mission. They time it just perfectly, as it is night, and the full moon. They only come at high tide. As they exit, they begin to reproduce, the females laying over 5,000 eggs, which the males compete eagerly to fertilize. They not only come ashore to breed, but also to moult into new skin. When they finished moulting, they will leave, back, into the deep. But this mass spawning attracts the attention of many animals. Rhamphorhynchus fly down. These nocturnal sea pterosaurs await the Mesolimulus spawning. They use their long, curved beaks to dig into the sand, then pluck out the eggs and eat them. Some Rhamphorhynchus decide to dive into the shallow waters to fish. They all dive into the shallow corals and swim down, attacking fish, and occasionally running on the sea floor, plucking worms and other fish here. Some finds hermit crabs in stolen shells. They use their long pointed curved beaks to fish the hermit crab out, and then, now out of its shell, and with no armour, is eaten. But they always take a big risk in doing this. Predators are on the lookout. A few Aspidorhynchus are waiting in coral caves, waiting, for the pterosaurs to swim by. One swims close enough. Suddenly, he snaps and grabs the pterosaur by the neck, killing it instantly. He drags his prey into the coral cave to feed on. Rhamphorhynchus continue their foray. The shallows also turn alive in the night in other ways. Some belemnites arrive to feed. A few adult Ophthalmosaurus arrive. They use their giant eyes to pluck food from the dark, then use their toothless bills to grab and eat their prey. These animals usually are seen in the open ocean, but will only come in the shallows at night to hunt. Once day light returns, they begin to go out into the open ocean, to hunt in the deep. Now that the Ophthalmosaurus is gone, the resident diurnal hunter awakens. A Geosaurus is looking for food. These marine crocodiles are rarely seen, and highly active. They look for prey in the crevices of rocks. This one finds a hiding fish and eats it. However, they are capable of hunting fast, free swimming fish. Sequence 4 A colony of mussels, anchored to the rock by their threadlike byssi, filter plankton from the seawater. Suddenly they sense a threat and they snap the shells shut. They have good reason to be worried, a deadly enemy of all coastal bivalves is hunting. A small mosasaur, Carinodens nears the colony. Mosasaurs would not usually pose much of a threat to such creatures, but this one does. It has blunt rounded teeth well adapted to crush armored prey. The male Carinodens flicks out his forked tongue to smell out the mollusks. When he finds the colony, he lunges forward and tears many of the mussels from the rock, crushes them with his powerful jaws and swallows them. He feeds on the mussels until he is full, at which point he swims away into deeper water. But he must be careful, many other mosasaurs live in the Netherlands that are more than capable of killing and devouring a Carinodens. A scallop swims by and the Carinodens catches it with hardly any effort. A Squalicorax shark swims by looking for an easy meal, but it knows better than to try to attack a Carinodens. Other predators have no difficulty in doing so. The Carinodens male has just enough time to swim off to side as a pair of massive jaws rush past. The attacker is a Mosasaurus, one of the largest mosasaur species, and also one of the most aggressive. The Carinodens manages to outswim its attacker but the Mosasaurus is hungry and will not give up easily. Our male quickly swims into a cave too narrow for the Mosasaurus to follow. Once the predator swims away, our Carinodens swims out and takes a breath at the surface. Then he swims back into the safety of the shallows. Sequence 5 Sequence 6 In the vast Western Interior Seaway, a huge shoal of Niobradines arrive, billions of them. Thus starting, the annual, Niobradine Run. They are similar to sardines, and arrive here to spawn. But this attracts many predators. So many predators, it is baffling. The first to arrive are the fishbirds, or Ichthyornis. They dive into the water and begin to pluck them from the shoal, surface, and feed. The next to arrive are the American toothed grebes, or Hesperornis, which are not related to grebes. They swim in and feed ravenously. This attracts some creatures, from the deep. Tusoteuthis use lights to trick the fish into swimming into their beaks. Other, smaller, tropical squid, only a foot long, arrive to attack. They are joined by belemnites, and both species display colour to communicate an attack on the shoal. But they are becoming prey themselves too, adding to the banquet. Cimolichthys arrive and target the squid. Bulldog Tarpon (Xiphactinus) arrive too. They are usually highly aggressive, and cannibalistic, but now these giant fish hunt cooperatively to catch these fish. The hunt continues. Then, come the most sophisticated of hunters, the Platecarpus. They arrive and send out clicks to launch an attack. This pod is enormous, 50 strong. They split up into different groups, and launch separate attacks on squid, belemnites, and the Niobradine. The mosasaurs are the most sophisticated in their attacks, separating some Niobradine into smaller, more manageable shoals. The sheer size makes it hard to hunt. Soon, the other animals turn their attention to the massive bait ball the Platecarpus have created. The opportunity to eat from this shoal is very quick. In less than five minutes, this shoal will be gone. Other Platecarpus arrive to make other bait balls themselves, but the fish use their sheer numbers to avoid this from happening, so they turn their attention to the bait ball at hand. This attracts animals who would usually never attack Niobradine. A Tylosaurus appears and lunge feeds, but the fish are so quick, he only gets a few in his mouth. Dolichorhynchops, Squalicorax, and Bonnerichthys arrive. Now, the shoal will last only a minute. The Tylosaurus must aim this next attack carefully, and time is carefully. His window of opportunity is so thin, there may not be another chance. But suddenly, one of the Platecarpus pods drives the tropical squid and belemnites into the bait ball, adding to the numbers. His window is slightly less thin now. But as a Bonnerichthys lunges, he knows that the time is now. There is no second chance. The Platecarpus have blocked all exits for the Niobradine. He lunges, opens his mouth, and cashes in. He has more than fifty fish in his mouth. The carnivores very quickly, in the matter of thirty seconds, eat all the remaining fish. The sheer number of fish is so great, that the vast majority survive, and will go off to spawn. No matter how many predators there area, the fish will survive. Sequence 7 Off the coast of Mongolia, Brodavis fly in. The nesting grounds here are just perfect for the Brodavis. They come here to breed. Some land on the desert beach. Others, make a more colourful entrance. They surf the waves onto the beach. They have all mated, and now search for a perfect space to lay eggs. They dig a small impression, and then lay their eggs, before sitting on it. To avoid conflict, they build each nest just beyond pecking reach. While the males sit on the nests, the females fly out into the shallow seas to feed. The sands blown in by a sandstorm weeks ago brought plenty of nutrients and fueled life here. Now, an abundance of squid and fish are here. The Brodavis dive in and snap fish and squid up. Once they catch food, they go to the surface, and feed on their catch. Unlike other hesperornids, they kept their ability to fly, and for good reason. Suddenly, some Brodavis frantically fly up. A juvenile Mosasaurus is hunting. He goes after the clueless. He spots one and lunges, but he misses. He sees one eating his catch at the surface. He rushes up and plucks the bird from the surface. He dives down with a new meal. On land too, there are threats. As the Brodavis are guarding the nest, a Velociraptor walks nearby. This is very rare to see a Velociraptor so close to the coast. He wasn't waiting, he just happened to stumble upon the birds. As he goes around the colony, he seems to be taking his time. The Brodavis begin to send wave calls of panic around. He knows he's been spotted. As he approaches a nest, the guarding Brodavis snaps at him, and he's forced back. The Brodavis have no worries themselves. He's after the eggs. He tries to sneak up, but a Brodavis from behind caws, and soon the guardian of his target nest caws, and he's forced to back off. He continues his search. Suddenly, he grabs a full grown adult by the neck and runs off from the colony. He goes inland, and uses his claws to cut it open. He was never after the eggs. He begins to feed on the dead bird. This is the only case of a Velociraptor ever going to the coast, and entering a Brodavis colony. The colony however, wait. Then, the females return from fishing. The females land on the beach and walk through the colony. One female walks far inland into find her mate. She tries to listen for his calls. There is no response. Then, she hears him, and they reunite. She feeds him the squid, and they huddle together. Others, aren't so lucky. A female returns to find her nest unguarded and feathers all around. She sits down on the nest. Other males wait for their mates to return, but they never come back. The desert coast is the beginning of the ocean. The most dynamic of all ocean habitats. This is the habitat that leads to the shallows. However, the shallows soon give way, to the deep blue. Trivia *The Triassic China sequence is split up into two parts, Tanystropheus and Atopodentatus. *The Jurassic Germany sequence is split up into four parts, one with Mesolimulus, the second with Rhamphorhynchus, the third with Ophthalmosaurus, and the fourth with Geosaurus.